Being an IT Consultant, this is one of the most important questions you will ever ask and any could ever answer. So here goes...
Backing up of Data is one of the most critical issues in IT, that businesses fail to grasp at first (that is until everything dies and there's no way to recover it), backing up your own personal data is just as important, but you wont be financially bankrupt (unless your working on a freelance project). So on that note...
At the top of the Backup Food chain is DR (Disaster Recovery), this is an exceptionally heavy and dull subject, but basically it is the ability to bring your entire systems back up and running, using a separate location that contains a duplicate of... everything.
Most businesses use either Net Backups and a SAN (Storage Area Network), this is a farm of disks that contain all the important data. There is also something called retention periods, but this really does not comply for personal use, just backup what you want when you fell you need to.
You will be aiming for backups to CD or DVD (using Windows Backup or Nero etc...) to burn it to and to store it until you need it. I used to use a tape format called DLT this is very good and can last a while for uses (over a year per tape). Seeing as every tape is about £60 and a drive can be £500-£2000, I ditched it for the more cost effective method of CD/DVDs. All my Projects are on a Network Drive and all my tutorials are backed up on DVD or CD, and stored in CD Case for reference.
That's it really. All I can advise is backup and keep it, get rewritable to save wastage of repeating the same data onto different disks.
Sorry to be sooo dull, but it is a dull subject.
Chris (formerly R@nSiD)
When the power of love overcomes the love of power the world will truely know peace - Jimmy Hendrix
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